What is CVE-2026-39844?

CVE-2026-39844 is a medium-severity vulnerability in Zauberzeug Nicegui, classified under Path Traversal. CVSS score: 5.9/10. Published 2026-04-08.

How severe is CVE-2026-39844?

Medium severity. CVSS v3 base score is 5.9 out of 10.

Path Traversal in Zauberzeug Nicegui

CVE-2026-39844

NiceGUI is a Python-based UI framework. Prior to 3.10.0, Since PurePosixPath only recognizes forward slashes (/) as path separators, an attacker can bypass this sanitization on Windows by using backslashes (\) in the upload filename. Appli…

Vulnerability class: Path Traversal (Directory Traversal)

EPSS: 0.001 (20.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N.

Affected products

Zauberzeug Nicegui — versions < 3.10.0

Weakness classification (CWE)

CWE-22 — Path Traversal

References

https://github.com/zauberzeug/nicegui/security/advisories/GHSA-w8wv-vfpc-hw2w (x_refsource_CONFIRM)
https://github.com/zauberzeug/nicegui/commit/d38a702e3af2da5b0708f689be8d71413fc77056 (x_refsource_MISC)
https://github.com/zauberzeug/nicegui/releases/tag/v3.10.0 (x_refsource_MISC)

Frequently asked questions

What is CVE-2026-39844?: CVE-2026-39844 is a medium-severity vulnerability in Zauberzeug Nicegui, classified under Path Traversal. CVSS score: 5.9/10. Published 2026-04-08.
How severe is CVE-2026-39844?: Medium severity. CVSS v3 base score is 5.9 out of 10.